OVEREXPRESSION OF MUTANT P53 AND C-ERBB-2 PROTEINS AND BREAST-TUMOR TAKE IN MICE

We established a panel of 17 xenografts from primary human breast carc inomas. We examined which characteristics of the original tumours and the xenografts facilitate growth in animals. Tumours expressing medium or strong immunoreactivity for p53 protein had significantly (P < 0.0 5) higher incidence (92%.) of in vivo tumour take than those showing w eak or negative immunoreactivity (9.1%). No such association was obser ved between either c-erbB-2 or epidermal growth factor receptor (EGFR) expression in the original tumours and their in vivo tumour take. Fol lowing subcutaneous (s.c.) transplantation of original breast tumours or established xenografts, 7/17 tumours showed metastatic disease spre ad to distant sites (mainly lungs). This study suggests that selective growth of highly aggressive tumours occurs during in vivo propagation of malignant tumours, and these tumours will be of particular interes t in evaluating various chemotherapeutic agents for breast cancer mana gement.